Characteristics of a rifle or heavy machine gun are determined according to whether the user wants to rapidly sight and fire and whether the user wants to accurately sight a target. In general, rifles or heavy machine guns sight a target by aligning a line of sight of a rear sight and a front sight. The sighting performed by the aligning of the line of sight of the front sight positioned at an end of a gun barrel and the rear sight positioned at an upper portion of a gun body allows the user to accurately fire according to their ability.
However, when the sighting is performed using both the rear sight and the front sight, it is difficult to align the line of sight due to even small vibrations or tremors, and it is difficult to rapidly sight a target at a short distance or in an urgent situation.
That is, in such situations, complicated processes, such as capture and confirmation of a target, alignment of a line of sight, sighting, etc., and time are required. In addition, since the front sight and the rear sight are themselves very small, they are sensitive to even small vibrations when the front sight and the rear sight are accurately aligned. Moreover, when a user excessively concentrates on the alignment of the line of sight, the user s sight is focused on the front sight and the rear sight rather than the target or front circumstances. Thus, the user focuses too much attention on the alignment of the line of sight to the detriment of other duties such as firing or coping with urgent situations.
Accordingly, to cope with the difficulty in the alignment of the line of sight and raise the accuracy of sighting, a sighting device equipped with a telephoto lens has been proposed. However, an optical sighting device equipped with a telephoto lens is sensitive to even small vibrations when magnification increases due to the use of the telephoto lens. Thus, there is still a difficulty in rapid sighting.
To address these problems, a dot sighting device in which a no magnification or low magnification lens is used in an optical sighting device, and an aiming point only is simply used without a complicated line of sight has been proposed.
Optical dot sighting devices with no magnification (low magnification) can simply and rapidly sight a target, and are very useful in urgent situations or for short distances. In particular, time spent in alignment of the line of sight can be saved, sighting is itself performed such that a dot image is positioned to coincide with a target, and thus the user does not have to devote all of their attention to the alignment of the line of sight. Ultimately, rapid and accurate sighting are possible, and attention can be focused on other urgent situations.
However, conventional dot sighting devices are devices for monocular vision in which a user has to watch a sight mirror with only one eye. Thus, it takes a long time to sight a target, and visual problems also occur.
FIG. 1 is a schematic cross-sectional view of a conventional dot sighting device 1 for monocular vision. Referring to FIG. 1, in the conventional dot sighting device 1, the inside of the dot sighting device 1 is aligned using a rifle barrel alignment terminal 3 through a fixed grille 11, and then light emitted from a LED light source 5 is reflected from a reflection mirror 7, whereby an observer confirms an object with one eye. In general, a front surface (inside of the sighting device) of the reflection mirror 7 is coated in order to reflect the light emitted from the LED light source 5, and curved surfaces of the front surface and a rear surface of the reflection mirror 7 are spherical, and have the same curvature.
A dot image reflected from the reflection mirror 7 is sighted to coincide with a target object viewed through a protective window 9 at no magnification, whereby a user fires at the target object when the dot image reflected from the reflection mirror 7 coincides with the target object. Thus, the sighting can be easily performed.
More particularly, the light irradiated from the LED light source 5 disposed in the dot sighting device 1 is reflected from the reflection mirror 7, and incident on the eye of an observer in parallel. The direction in which the parallel light is reflected should coincide with a bullet firing axis of a gun barrel. If the parallel degree of the dot sighting device 1 does not coincide with the bullet firing axis of the gun barrel, a user cannot hit the target object even when a dot of the light irradiated from the LED light source 5 coincides with the target object. Thus, to coincide the parallel degree of the dot sighting device 1 with the bullet firing axis of the gun barrel, the rifle barrel alignment terminal 3 having vertical and horizontal adjustment functions is operated to coincide an optical axis of an inner barrel with the bullet firing axis of the gun barrel.
FIG. 2 is a schematic view illustrating the case in which parallax occurs in the conventional dot sighting device of FIG. 1. However, as illustrated in FIG. 2, if the width of the reflection mirror 7 is not greater than a distance between pupils of a user, binocular vision obtained by overlapping of both eyes does not exist. In this state, when an external object is viewed through the reflection mirror 7, it is impossible to obtain information on the external object by binocular vision. Thus, the external object is viewed by an eye superior to the other eye, or double vision of the object occurs. In this case, eye strain is caused by not being able to accurately obtain information on the external object.
To address this problem, if only the size of a sight mirror, i.e., a protective mirror and the reflection mirror is simply increased, as illustrated in FIG. 2, parallax of the reflection mirror 7 itself occurs due to an increase of aberration of an ambient portion of the reflection mirror 7. Thus, the parallel degree of the dot sighting device does not coincide with the bullet firing axis of the gun barrel. The occurrence of parallax reduces the accuracy of sighting the target. FIG. 2 illustrates parallax in which light rays reflected from a general spherical reflection surface are not parallel to each other.
In addition, in conventional dot sighting devices, as illustrated in FIG. 1, regardless of the distance to the target, light irradiated from the LED light source 5 along the same optical axis is reflected from the reflection mirror 7, whereby a dot image is focused on the target. However, gravity continuously acts on a bullet after the bullet is fired until it hits the target, and thus the farther away the target, the greater a path of the bullet is changed. In conventional dot sighting devices, to reflect the change in the path of the bullet according to the distance, an optical axis of a main body of the dot sighting device and the parallel degree of the bullet firing axis of the gun barrel are mechanically adjusted. Thus, when the distance to the target material is suddenly changed, users cannot rapidly cope with the situation.
Moreover, the light irradiated from the LED light source uses a single reticle, and thus the same dot with respect to all targets is always formed. However, targets of a heavy machine gun, such as human, tanks, and aircraft each have different characteristics. For example, in the case of firing at aircraft, sighting and firing should be performed taking into consideration the velocity of the aircraft. Thus, in a conventional dot sighting device, it is difficult to perform accurate sighting and firing taking into account characteristics of targets.